Beneficial Insects: Your Garden’s Most Powerful Allies

Many common insects are actually good for your garden.

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Other Beneficials

Dragonflies: Often called “darning needles,” dragonflies and their smaller cousins, damselflies, scoop up mosquitoes, gnats, and midges, cramming their mouths with prey as they dart in zig-zag patterns around marshes and ponds.

Lacewings: The brown or green, alligator-like larvae of several species of native lacewings prey upon a variety of small insects, including aphids, scale insects, small caterpillars, and thrips. Adult lacewings are delicate, ½- to 1-inch 82green or brown insects with large, transparent wings marked with a characteristic fine network of veins. They lay pale green oval eggs, each at the tip of a long, fine stalk, along the midrib of lettuce leaves or other garden plants.

True bugs: True bug is the scientifically correct common name for a group of insects. This group does include several pest species, but there are also many predatory bugs that attack soft-bodied insects such as aphids, beetle larvae, small caterpillars, pear psylla, and thrips. Assassin bugs, ambush bugs, damsel bugs, minute pirate bugs, and spined solider bugs are valuable wild predators in farm systems.

Spiders and mites: Although mites and spiders are arachnids, not insects, they are often grouped with insects because all belong to the larger classification of arthropods. Predatory mites are extremely small. The native species found in trees, shrubs, and surface litter are invaluable predators. Phytoseiid mites control many kinds of plant-feeding mites, such as spider mites, rust mites, and cyclamen mites. Some also prey on thrips and other small pests. Many types of soil-dwelling mites eat nematodes, insect eggs, fungus gnat larvae, or decaying organic matter.

It’s unfortunate that so many people are scared of spiders, because they are some of the best pest predators around. We are most familiar with spiders that spin webs, but there are many other kinds. Some spin thick silk funnels; some hide in burrows and snatch insects that wander too close, while others leap on their prey using a silk thread as a dragline.

Encouraging Beneficials

The best way to protect beneficial insects is to avoid using toxic sprays or dusts in the garden. Even organically acceptable sprays such as insecticidal soap and neem can kill beneficial species, so use them only when absolutely necessary to preserve a crop and then only on the plants being attacked. Be careful when you hand pick or spray pest insects, or you may end up killing beneficial insects by mistake. While many beneficials are too small to be seen with the unaided eye, it’s easy to learn to identify the larger common beneficials such as lacewings, tachinid flies, and lady beetles.

You can make your yard and garden a haven for beneficials by taking simple steps to provide them with food, water, and shelter.

Food sources: A flower bed or border of companion plants rich in pollen and nectar, such as catnip, dill, and yarrow, is a food source for the adult stages of many beneficials, including native bees, lacewings, and parasitic wasps.